Medical cauterization snare assembly and associated methodology

ABSTRACT

A medical cauterization snare assembly with a tubular member, an electrically conductive cauterization loop ejectable from a distal end of the tubular member, and a capture pouch also ejectable from the distal end of the tubular member. The pouch is attached to an auxiliary loop which has a size larger than that of the cauterization loop. Alternatively, the tubular member is formed at its distal end with a first port or opening and in a distal end portion with a second port or opening spaced from the first port or opening. The two ports or openings both face in a distal direction (i.e., away from the user). The cauterization loop is alternately ejectable from and retractable into the first port or opening, while the capture pouch is separately ejectable from the second port or opening. Alternatively, the capture pouch is attached to the cauterization loop, to only a proximal portion of the loop to divide the loop&#39;s area into a proximal section covered by the pouch and an open or uncovered distal section.

FIELD OF THE INVENTION

This invention relates to a surgical instrument assembly for use inremoving and retrieving selected tissues from internal body cavities ofa patient. This invention more specifically relates to an instrumentassembly for use in snare cauterization operations. This invention alsorelates to an associated method for severing internal organic tissuesand retrieving the severed organic tissues from the patient. Theinvention is particularly useful in the removal of polyps, for example,from the colon of a patient.

BACKGROUND OF THE INVENTION

In a conventional endoscopic snare operation, an endoscope is insertedinto an internal cavity of a patient, e.g., into the colon, and is usedto locate abnormal tissue growths such as polyps in the internal cavity.Upon the locating of a polyp or other growth which is to be removed, awire extending through a tube in the biopsy channel of the endoscope isslid in the distal direction so that a cauterization loop connected tothe wire is ejected from the distal end of the tube and the endoscope.The loop and the endoscope are manipulated from outside of the patientto pass the loop over the polyp or growth. The wire is then withdrawn inthe proximal direction to tighten the loop around a base region or neckof the polyp. Once the loop is in contact with the base region of thepolyp, an electrical current is conducted through the loop via the wire.Generally, as the loop is closed about the base region of the polyp,electrical current is transmitted through the narrowed organic tissuesand thereby generates therein heat sufficiently great to cut andcauterize.

Once a polyp is severed by such a snare cauterization technique, itfrequently becomes difficult to capture the polyp and retrieve it fromthe patient. Sometimes the cauterization loop is used in an effort toensnare the polyp. Other capture techniques involve the use of forcepsor the application of suction. In using forceps, the snare cauterizationtube is removed from the biopsy channel of the endoscope and replacedwith the forceps. In using suction, a vacuum is applied via a suctionchannel of the endoscope.

No matter which specific technique is used, the polyp frequently escapesfrom the capturing instrumentality and falls away into the colon (orother cavity). Especially in cases where the polyp is large, the effortand time expended in retrieving the severed polyp may rival or evenexceed the effort and time required to locate and sever the polyp. Insome cases, the endoscope must be removed without the polyp and thepatient given an enema in an attempt to flush out the polyp from thecolon.

Furthermore, there are numerous cases where a severed polyp is neverrecovered. Sometimes, the polyp is macerated during the retrievalattempt. In all such cases, the pathologist is unable to determinewhether the polyp contains carcinoma in situ (localized) or infiltrativecarcinoma (spread). The patient must then undergo a colon resection,sometimes unnecessarily.

In any event, the manipulations necessary to remove a severed polypgenerally increase the trauma to the patient, the expense of the surgeryand the hospitalization time. There is now a long-felt need to improvethe snare cauterization technique to facilitate the capture andretrieval of severed polyps.

U.S. Pat. No. 5,201,740 to Nakao et al. provides a solution to theabove-described problems in polyp removal. Pursuant to the disclosure ofthat patent, snare cauterization operations are performed with asurgical instrument assembly comprising a tubular sheath member carryinga metallic cauterization loop and a metal wire operatively connected tothe loop, the wire passing longitudinally through the sheath. Anelectrical supply is operatively connectable to the wire, while aflexible web member is connected to the loop to form a capture pocket,the loop defining a mouth opening of the pocket. During use of the snarecauterization loop, the web member is passed over and substantiallysurrounds a polyp. The pocket captures the polyp at the same time thatthe cauterization loop is energized to effectuate a severing of thepolyp.

This cauterization snare assembly with attached pocket is a substantialadvance over conventional polyp removal techniques. However, the snareassembly is generally useful for collecting only one polyp from apatient. Owing to the cumulative heating of the points of attachment ofthe capture pouch to the cauterization loop, the capture pouch can beseparated from the cauterization loop after polyp capture has occurred.Thus, where the patient has multiple polyps, multiple cauterizationsnare assemblies must be used.

OBJECTS OF THE INVENTION

An object of the present invention is to provide an improved instrumentassembly for the removal of polyps and other organic tissue parts frompatients, particularly an instrument assembly useful for removingmultiple polyps from a patient's colon.

Another particular object of the present invention is to provide such aninstrument assembly which is simple to manufacture and thereforeinexpensive.

A further particular object of the present invention is to provide suchan instrument assembly which is easy to use.

Yet another object of the present invention is to provide an associatedmethod for the removal of tissue samples from a patient.

These and other objects of the present invention will be apparent fromthe descriptions and drawings herein. It is to be noted that each objectis attained by one or more embodiments of the invention. No singleembodiment, however, need attain all objects stated implied herein.

SUMMARY OF THE INVENTION

The present invention is directed to a medical cauterization snareassembly comprising a tubular member, an electrically conductivecauterization loop ejectable from a distal end of the tubular member,and a capture pouch also ejectable from the distal end of the tubularmember. In one embodiment of the invention, the pouch is attached to anauxiliary loop which has a size larger than that of the cauterizationloop so that a simultaneous retraction of the two loops into the distalend of the tubular member results in a completed contraction of thecauterization loop while a portion of the auxiliary loop still remainsoutside of the tubular member.

The difference in the sizes of the cauterization loop and the auxiliaryloop minimize contact between the loops and thus reduces thetransmission of heat energy to the auxiliary loop and the pouch. It isto be noted that a severed polyp is easily captured by a pouch even ifthe pouch is partially opened. The severed polyp is small and light andis easily entrained by a partially closed pouch.

In a more particular embodiment of the present invention, thecauterization loop and the auxiliary loop are both connected to a commonwire slidably extending through the tubular member. Thus, both loops areejected and retracted by manipulation of a single wire. Preferably, atleast a portion of the auxiliary loop is made of a heat resistantmaterial such as nylon

Pursuant to another feature of the present invention, the cauterizationloop and the auxiliary loop are at least approximately coplanar in theexpanded configuration they assume upon ejection from the tubularmember. Generally, the loops are biased by internal spring forces toassume the expanded configuration. When disposed inside the tubularmember, the loops are held in a contracted configuration.

Pursuant to another feature of the present invention, the auxiliary loopis bent out of a planar configuration. Thus, the expanded auxiliary loopmay have a cup shaped form partially coplanar with the cauterizationloop and partially projecting from the plane of the cauterization loop.

A related medical cauterization snare assembly comprises, in accordancewith the present invention, a tubular member, an elongate electricallyconductive element slidably disposed at least partially in the tubularmember, and a cauterization loop made of an electrically conductivematerial and provided at one end of the electrically conductive elementfor alternate ejection from and retraction into a distal end of thetubular member. The snare assembly additionally comprises an auxiliaryloop larger than the cauterization loop, an elongate connector element,and a pouch member. The auxiliary loop is formed at one end of theconnector element whereby the auxiliary loop is alternately ejected fromand retracted into the tubular member. The pouch member is attached tothe auxiliary loop so as to form a capture pocket with the auxiliaryloop defining a mouth or opening of the capture pocket.

The electrically conductive element generally takes the form of a wire,while the connector element may be a stiff fiber or thread fastened at aproximal end to the wire and connected at a distal end to the auxiliaryloop. Whereas the wire has a length on the order of one-half meter toone meter, the fiber or thread is preferably connected to the wire at apoint spaced only a few centimeters from the proximal end of thecauterization loop.

An associated minimally invasive surgical method utilizes theabove-described cauterization snare assembly and comprises inserting adistal end portion of the tubular member into a patient and thereafterpushing the electrically conductive element to eject the cauterizationloop from the tubular member, the cauterization loop expanding from acollapsed configuration into an at least partially opened configurationupon ejection of the cauterization loop from the tubular member. Themethod also comprises pushing the connector element to eject theauxiliary loop from the tubular member after the inserting of the distalend portion of the tubular member into the patient. Upon this ejection,the auxiliary loop expands from a collapsed configuration into an atleast partially opened configuration. Thereafter the tubular member andthe electrically conductive element are manipulated to pass the expandedcauterization loop and the expanded auxiliary loop over a lump of tissueinside the patient. Then the electrically conductive element and theconnector element are pulled to simultaneously draw the cauterizationloop and the auxiliary loop into the distal end portion of the tubularmember, thereby contracting the cauterization loop and the auxiliaryloop. An electrical current is passed through the cauterization loopduring the pulling of electrically conductive element and the connectorelement and the contracting of the cauterization loop and the auxiliaryloop, thereby severing the lump of tissue. The severed lump of tissue iscaught in the capture pocket upon a partial closure thereof owing todrawing of the auxiliary loop into the distal end portion of the tubularmember. A portion of the auxiliary loop remains outside of the tubularmember after the cauterization loop has been completely withdrawn intothe distal end portion of the tubular member.

In a second embodiment of a medical cauterization snare assembly inaccordance with the present invention, the tubular member is formed atits distal end with a first port or opening and in a distal end portionwith a second port or opening spaced from the first port or opening. Thetwo ports or openings both face in a distal direction (i.e., away fromthe user). The cauterization loop is alternately ejectable from andretractable into the first port or opening, while the capture pouch isseparately ejectable from the second port or opening.

In this second embodiment of the invention, the spacing between theports or openings at the distal end of the tubular member facilitatesthe ejection and placement of the capture pouch after the cauterizationloop has been positioned over a target tissue lump. It is to be notedagain that a severed polyp is easily captured by a pouch even if thepouch is still open. Thus, placement of an open pouch over the polyp inusing this second embodiment of the invention is adequate to entrain thepolyp after severing thereof by the cauterization loop.

In the second embodiment of the present invention, the tubular member ispreferably formed with a partition member dividing a lumen of thetubular member into a first channel and a second channel. The firstchannel communicates with the first port or opening, while the secondchannel communicates with the second port or opening. The wire to whichthe cauterization loop is connected slidably extends through the firstchannel, whereas the elongate member to which the pouch is attachedslidably traverses the second channel.

A medical cauterization snare assembly incorporating this secondembodiment of the present invention comprises a tubular member providedat a distal end with a first port or opening and in a distal end portionwith a second port or opening spaced from the distal end, the first portor opening and the second port or opening facing in a distal direction.The cauterization snare assembly further comprises an elongateelectrically conductive element (e.g., wire) slidably disposed at leastpartially in the tubular member, a cauterization loop made of anelectrically conductive material and provided at one end of theelectrically conductive element for alternate ejection from andretraction into the distal end portion of the tubular member via thefirst port or opening. An elongate slider element is slidably disposedat least partially in the tubular member, and an auxiliary loop isprovided at one end of the elongate slider element for alternateejection from and retraction into the distal end portion of the tubularmember via the second port or opening. A pouch is attached to theauxiliary loop so as to form a capture pocket with the auxiliary loopdefining a mouth or opening of the capture pocket. As discussed above,the tubular member is preferably formed with a partition member dividinga lumen of the tubular member into a first channel and a second channel,the first channel communicating with the first port or opening, thesecond channel communicating with the second port or opening, theelectrically conductive element slidably extending through the firstchannel, the elongate slider element slidably extending through thesecond channel.

In accordance with another aspect of the present invention, the tubularmember of the second embodiment of the invention is provided on asurface of the partition member between the first port or opening andthe second port or opening with a visually perceptible marker. Themarker is exemplarily a red spot. The marker is used as a visual cue toalert the user as to the orientation of the distal end portion of thetubular member and, accordingly, the orientation of the pouch.

The various embodiments of the present invention preferably include atether or string provided on the capture pouch for facilitating aclosure of the pouch about a severed polyp.

In a third embodiment of a medical cauterization snare assembly inaccordance with the present invention, there is no auxiliary loop.Instead, the capture pouch is attached to the cauterization loop. Thecauterization loop in the opened or expanded configuration defines orbounds an area. The pouch is attached to only a proximal portion of theloop to divide the loop's area into a proximal section covered by thepouch and an open or uncovered distal section. Essentially, only theexposed part of the cauterization loop does the cutting and generatesheat. Accordingly, the pouch is not unduly heated and remains attachedto the cauterization loop after completion of a polyp retrievaloperation. The instrument assembly may then be reinserted into a patient(e.g., through the biopsy channel of an endoscope).

Pursuant to another feature of the present invention, the pouch of thisthird embodiment is fixed to the cauterization loop at a pair of opposedpoints on the loop. A rim of the pouch extends across the opencauterization loop from one side thereof to another.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view of a cauterization snare assemblyin accordance with the present invention.

FIGS. 2A through 2E are partially cross-sectional views of a patient'scolon and partially schematic perspective views of an endoscopeemploying the cauterization snare assembly of FIG. 1, showing successivesteps in a polyp retrieval method pursuant to the invention.

FIG. 3 is a schematic perspective view of another cauterization snareassembly in accordance with the present invention.

FIGS. 4A through 4D are partially cross-sectional views of a patient'scolon and partially schematic perspective views of an endoscopeemploying the cauterization snare assembly of FIG. 3, showing successivesteps in a polyp retrieval method pursuant to the invention.

FIG. 5 is a schematic perspective view of a further cauterization snareassembly in accordance with the present invention.

FIG. 6 is a schematic perspective view of yet another cauterizationsnare assembly in accordance with the present invention.

FIGS. 7A through 7F are partially cross-sectional views of a patient'scolon and partially schematic perspective views of an endoscopeemploying the cauterization snare assembly of FIG. 5, showing successivesteps in a polyp retrieval method pursuant to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As illustrated in FIG. 1, a cauterization snare assembly 10 comprises atubular member 12 formed at its distal end with a first port or opening14 and in a distal end portion with a second port or opening 16 spacedfrom the first port or opening. The two ports or openings 14 and 16 bothface in a distal direction (i.e., away from the user). A cauterizationloop 18 is alternately ejectable from and retractable into port oropening 14, while a capture pouch 20 is separately ejectable from portor opening 16.

Tubular member 12 is preferably formed with a partition member 22dividing a lumen (not separately designated) of the tubular member intoa first channel 24 and a second channel 26. Channel 24 communicates withport or opening 14, while channel 26 communicates with port or opening16. Cauterization loop 18 is made of an electrically conductive materialand is connected to an elongate electrically conductive element in theform of a wire 28 slidably extending through channel 24. Wire 28 servesnot only to carry electrical current to cauterization loop 18 but alsofunctions to transmit mechanical compressive and tensile forces toenable an alternating ejection and retraction of the cauterization loop.Similarly, pouch 20 is attached to an elongate actuator element 30 whichslidably traverses channel 26 and enables a user to eject pouch 20 fromchannel 26 and alternately withdraw the ejected pouch back into channel26. More specifically, pouch 20 is attached via metal ringlets 29 to anauxiliary loop 31 provided at the distal end of actuator element 30.Auxiliary loop 31, as well as fibers of pouch 20, is preferably made ofa heat-resistant material such as nylon. Alternatively, auxiliary loop31 may be made of metal having a coating of a heat resistant materialsuch as nylon.

Ports or openings 14 and 16 are spaced from one another by a section 32of partition member or divider 22 which forms a shelf or an outer wallof the distal end portion of tubular member 12 and which partiallydefines or encloses the distal end portion of channel 24. The spacingbetween ports or openings 14 and 16 facilitates the ejection andplacement of capture pouch 20 after cauterization loop 18 has beenpositioned over a target tissue lump PLP (FIGS. 2A–2E). It is to benoted again that a severed polyp PLP is easily captured by pouch 20 evenif the pouch is still open. Thus, placement of an open pouch 20 over thepolyp PLP in using the cauterization snare assembly 10 of FIG. 1 isadequate to entrain the polyp after severing thereof by cauterizationloop 18.

FIG. 2A depicts a distal end portion of an endoscope insertion member 34inserted into a patient's colon CLN. Tubular member 12 is disposed in abiopsy channel 36 of endoscope insertion member 34. Light emitted byillumination optics 38 is reflected or scattered by the internal tissuesof colon CLN. The reflected or scattered light is detected viaadditional optics including a lens 40. Upon a visual detection of polypPLP, tubular member 12 is pushed in a distal direction, towards polypPLP, so that ports or openings 14 and 16 are disposed outside of biopsychannel 36, as shown in FIG. 2A. Then wire 28 is pushed in the distaldirection through channel 24 so that cauterization loop 18 is ejectedthrough port or opening 14. Endoscope insertion member 34, tubularmember 12 and/or wire 28 is then manipulated to position cauterizationloop 18 over polyp PLP, as shown in FIG. 2B. Elongate actuator element30 is subsequently shifted in the distal direction to eject auxiliaryloop 31 and pouch 20 from channel 26 through port or opening 16, asillustrated in FIG. 2C. Endoscope insertion member 34, tubular member 12and/or actuator element 30 is then manipulated to position auxiliaryloop 31 over polyp PLP (FIG. 2C.) Cauterization loop 18 is thenretracted back into channel 24 via port or opening 14, by a pulling ofthe wire 28 in the proximal direction. An electrical current is passedthrough cauterization loop 18 via wire 28 during the pulling of the wireand the contracting of cauterization loop 18, thereby severing polypPLP, as depicted in FIG. 2D. The severed polyp PLP is entrained by pouch20, which is then drawn in a proximal direction back towards port oropening 16. The entire instrument assembly, including endoscopeinsertion member 34, tubular member 12, actuator element 30, auxiliaryloop 31 and pouch 20, is then removed from the patient's colon CLN. Theinstrument assembly may be used again to extract further polyps (notshown) from the patient.

It is to be noted, as discussed in detail hereinafter, that auxiliaryloop 31 may be turned or bent, particularly at a distal end 42 (FIG. 1),to facilitate capture of polyp PLP. Also, a mark such as a red spot 44or 46 may be provided on a distal end of tubular member 12 to facilitatedetection of the angular orientation of tubular member 12 about itslongitudinal axis.

A medical cauterization snare assembly 50 as illustrated in FIG. 3 hasno auxiliary loop. Instead, a capture pouch or basket 52 is attached toa cauterization loop 54. Cauterization loop 54 in the opened or expandedconfiguration defines or bounds a generally almond-shaped area 56. Pouch52 is attached to only a proximal portion of cauterization loop 54 todivide the loop's area 56 into a proximal section 58 covered by thepouch and an open or uncovered distal section 60. Essentially, only anexposed part 62 of cauterization loop 54 implements tissue cutting andgenerates heat. Accordingly, pouch 52 is not unduly heated and remainsattached to cauterization loop 54 after completion of a polyp retrievaloperation. The cauterization snare instrument assembly 50 may then bereinserted into a patient.

Pouch 52 is attached to cauterization loop 54 via a plurality ofringlets 64. At two opposed points 66 and 68, pouch 52 is fixedlysecured to loop 54. A rim 70 of pouch 52 extends across the opencauterization loop 54 from one side thereof to another. Ringlets 64 maybe slidably attached or fixedly coupled to loop 54. In the former case,a string (not shown) may be connected to a proximal end of the pouch toensure a reopening thereof upon an ejection of the cauterization loop 54and pouch 52 from a distal end of a tubular member 72 upon a pushing ofan elongate actuator element or wire 73.

FIG. 4A depicts a distal end portion of an endoscope insertion member 74inserted into a patient's colon CNN. Tubular member 72 is disposed in abiopsy channel 76 of endoscope insertion member 74. Light emitted byillumination optics 78 is reflected or scattered by the internal tissuesof colon CNN. The reflected or scattered light is detected viaadditional optics including a lens 80. Upon a visual detection of apolyp PYP, tubular member 74 is shifted in a distal direction, towardspolyp PYP, so a distal end portion of the tubular member 74 is disposedoutside of biopsy channel 76, as shown in FIG. 4A. Wire 73 is thenshifted in the distal direction through tubular member 72 to eject pouch52 and cauterization loop 54. Upon ejection from tubular member 72,cauterization loop 54 (as well as all other loops disclosed herein)expands from a substantially closed or collapsed storage configurationinside the tubular member to an opened used configuration outside of thetubular member, the loop being formed with an inherent spring biastending to form the loop into the opened configuration. Endoscopeinsertion member 74, tubular member 72 and/or wire 73 is subsequentlymanipulated to position cauterization loop 54 and pouch 52 over polypPYP, as shown in FIG. 4B. After that positioning of the loop 54 andpouch 52, wire 73 is pulled in a proximal direction so thatcauterization loop 54 closed about polyp PYP (FIG. 4C) and iselectrically energized so that exposed port 62 of the cauterization loopcuts and cauterizes the polyp (FIG. 4D). The entire instrument assembly,including endoscope insertion member 74, tubular member 72,cauterization loop 54 and pouch 52, is then removed from the patient'scolon CNN. The instrument assembly may be used again to extract furtherpolyps (not shown) from the patient. That portion of loop 54 surroundingproximal section 58 may be coated with a heat-resistant material such asnylon to inhibit separation of pouch 52 from loop 54. In addition,ringlets 64 may be made of a heat-resistant material such aspolytetraflouroethylene which is not heat conductive.

As depicted in FIG. 5, another medical cauterization snare assembly 90comprises a tubular member 92, an electrically conductive cauterizationloop 94 ejectable from a distal end of the tubular member, and a capturepouch 96 also ejectable from the distal end of the tubular member. Pouch96 is attached via ringlets 97 to an auxiliary loop 98 which has a sizelarger than that of cauterization loop 94 so that a simultaneousretraction of the two loops 94 and 98 into the distal end of tubularmember 92 results in a completed contraction of cauterization loop 94while a portion of auxiliary loop 98 still remains outside of thetubular member. The difference in the sizes of cauterization loop 94 andauxiliary loop 98 minimize contact between the loops and thus reducesthe transmission of heat energy to the auxiliary loop and to pouch 96.Pouch 96 is attached directly to auxiliary loop 98 only and is at mostindirectly to cauterization loop 94. With respect to the sizes of loops94 and 98, auxiliary loop 98 has a circumference (distance around theloon) that is significantly larger than the circumference ofcauterization loop 94, so that a portion of the auxiliary loop canremain outside tubular member 92 (together with at least a portion ofpouch 96 and a captured polyp) after a completed retraction ofcauterization loop 94 into the tubular member during a simultaneousretracting of both loops into the tubular member. As shown in FIG. 5,pouch 96 is attached to auxiliary loop 98 about the circumferencethereof and is not attached to cauterization loop 94 about any portionof the circumference of loop 94.

Cauterization loop 94 is provided at the distal end of an electricallyconductive push rod or wire 100, whereas auxiliary loop 98 is attachedto the distal end of an ancillary elongate connector element or push rod102. Wire 100 and rod 102 pass through respective channels 104 and 106defined in tubular member 92 by a partition member 108.

As indicated by dashed or phantom lines 109 in FIG. 5, auxiliary loop 98may be bent or arced at a distal end 110 so as cup the distal end ofcauterization loop 94 and facilitate or enhance polyp captureoperations.

In a modified cauterization snare assembly 120 illustrated in FIG. 6, acauterization loop 122 and an auxiliary loop 124 carrying a pouch 126are connected to a common wire 128 slidably extending through a tubularmember 130. Thus, loops 122 and 124 are simultaneously ejected andretracted by manipulation of wire 128. A connector fiber 132 extendsfrom auxiliary loop 124 to wire 128. That connector fiber and auxiliaryloop 124 may be made of a heat resistant material such as nylon orcoated with a heat resistant material. Thus, at least a portion ofauxiliary loop 124 is made of a heat resistant material such as nylon.Auxiliary loop 124 is bent or arced at a distal end 134 so as cup thedistal end of cauterization loop 122 and facilitate or enhance polypcapture operations. Pouch 126 is attached directly to auxiliary loop 124only and is at most indirectly to cauterization loop 122 (via commonwire 128). With respect to the sizes of loops 122 and 124, auxiliaryloop 124 has a circumference (distance around the loop) that issignificantly larger than the circumference of cauterization loop 122,so that a portion of the auxiliary loop can remain outside tubularmember 130 (together with at least a portion of pouch 126 and a capturedpolyp) after a completed retraction of cauterization loop 122 into thetubular member during a simultaneous retracting of both loops into thetubular member. As shown in FIG. 6, pouch 126 is attached to auxiliaryloop 124 about the circumference thereof and is not attached tocauterization loop 122 about any portion of the circumference of loop122.

Cauterization loops 94 and 122 and the respective auxiliary loops 98 and124 are at least approximately coplanar in the illustrated expandedconfigurations the loops assume upon ejection from the respectivetubular member 92 and 130. Generally, the loops 94, 122 and 98, 124 arebiased by internal spring forces to assume the expanded configurationsupon release from the tubular members 92 and 130.

FIGS. 7A through 7F illustrate successive steps in the utilization ofsnare assembly 90 in a minimally invasive polyp removal operation. FIGS.7D through 7F are applicable to the use of snare assembly 120. A distalend portion of an endoscope insertion member 136 is inserted into apatient's colon PCN until a polyp PP is detected via endoscope optics138 and 140 (FIG. 7A). At that juncture, tubular member 92 is shifted bya user in a distal direction to eject a distal end portion of thetubular member from a biopsy channel 142 of the endoscope insertionmember 136. Subsequently, electrically conductive element or wire 100 ispushed in the distal direction to eject cauterization loop 94 fromtubular member 92 (FIG. 7B), the cauterization loop expanding from acollapsed configuration into an at least partially opened configurationupon escape from the tubular member. The instrument assembly ismanipulated by the user to place cauterization loop 94 over the polyp PP(FIG. 7B) and to tighten the cauterization loop about the polyp PP (FIG.7C). Connector element or push rod 102 is then shifted to ejectauxiliary loop 98 from tubular member 92 (FIG. 7D). Upon this ejection,auxiliary loop 98 expands from a collapsed configuration into an atleast partially opened configuration. Thereafter, the instrumentassembly 90 is manipulated to pass the expanded auxiliary loop 98 overpolyp PP. Electrically conductive element or wire 100 and connectorelement or push rod 102 may be simultaneously pulled to drawcauterization loop 94 and auxiliary loop 98 into the distal end portionof tubular member 92, thereby contracting the cauterization loop and theauxiliary loop. An electrical current is passed through cauterizationloop 94 during the pulling of wire 100 and push rod 102 and thecontracting of cauterization loop 94 and auxiliary loop 98, therebysevering polyp PP. The severed polyp PP is caught in the pouch 96 upon apartial closure thereof owing to drawing of auxiliary loop 98 into thedistal end portion of tubular member 92. A portion of auxiliary loop 98remains outside of tubular member 92 after cauterization loop 94 hasbeen completely withdrawn into the distal end portion of the tubularmember.

As shown in FIG. 3, snare assembly 50, as well as any of the snareassemblies disclosed herein, may be provided with at least one andpreferably two flexible tensile members or tethers 150 and 152 connectedto pouch 52 at proximal end points 154 thereof. Flexible tensile members150 and 152 are also connected to tubular member 72 at a pair of holes158 and 160 formed in tubular member 72 at points spaced from a distalend thereof. Tensile members 150 and 152 extend from flexible pouch 52into tubular member 72. Tensile members 150 and 152 are segments of asingle flexible tensile tether member (not separately designated whichextends through holes 158 and 160 in tubular member 72. A patch (notshown) may be disposed on an outer surface of tubular member 72 overholes 158 and 160 and over a bight portion 162 of the single tensilemember which is located outside the tubular member. The patch is a thinfilm of polymeric material which is heat shrunk tightly over the tubularmember 72. The patch ensures that bight portion 162 is not snagged onpossible protuberances inside the endoscope biopsy channel 76 (FIGS.4A–4D).

When cauterization loop 54 is ejected from tubular member 72, pouch orcapture pocket 52 slides along loop 54, staying outside of the tubularmember, as illustrated in FIG. 4D. In the event that the loop 54 issubsequently ejected again from the distal end of tubular member 72,tensile segments 150 and 152 hold the proximal end of pouch or capturepocket 52 so that the pouch slides back along the emerging loop 54 tobecome repositioned along the loop as illustrated in FIG. 3.

The tensile tether members 150 and 152 ensures that the pouch 52 canremain outside the tubular member 72 and yet can be reopened orrepositioned in the event it is necessary or desirable to eject the loop54 again. If tensile segments 150 and 152 were attached to loop 54 orwire 73, as it is in some prior art pouches, a polyp contained in pouchor capture pocket 52 would be mashed owing to a dragging of the pocketand its contents into tubular member 72.

It is to be noted that any of the pouches or capture pockets disclosedherein are preferably provided with at least one and preferably twoflexible tensile members or tethers for this redeployment purpose. Thisfeature of the present cauterization snare assemblies is disclosed inU.S. Pat. No. 5,759,187.

Although the invention has been described in terms of particularembodiments and applications, one of ordinary skill in the art, in lightof this teaching, can generate additional embodiments and modificationswithout departing from the spirit of or exceeding the scope of theclaimed invention. Accordingly, it is to be understood that the drawingsand descriptions herein are proffered by way of example to facilitatecomprehension of the invention and should not be construed to limit thescope thereof.

1. In a medical cauterization snare assembly comprising a tubularmember, an electrically conductive loop ejectable from a distal end ofsaid tubular member, and a capture pouch also ejectable from said distalend of said tubular member, said loop being a first loop having a firstsize, the improvement wherein said pouch is attached to a second loophaving a second size larger than said first size so that a simultaneousretraction of said first loop and said second loop into said distal endof said tubular member results in a completed retraction of said firstloop while a portion of said second loop still remains outside of saidtubular member.
 2. The snare assembly set forth in claim 1 wherein saidfirst loop and said second loop are both connected to a common wireslidably extending through said tubular member, at least a portion ofsaid second loop being made of a heat resistant material.
 3. The snareassembly set forth in claim 2 wherein said heat resistant material isnylon.
 4. The snare assembly set forth in claim 1 wherein said firstloop and said second loop are at least approximately coplanar in anexpanded configuration upon ejection from said tubular member.
 5. Thesnare assembly set forth in claim 4 wherein said second loop is bent outof a planar configuration.
 6. The snare assembly set forth in claim 1wherein said second loop is bent out of a planar configuration.
 7. Amedical cauterization snare assembly comprising: a tubular member; anelongate electrically conductive element slidably disposed at leastpartially in said tubular member; a first loop having a firstcircumference and made of an electrically conductive material andprovided at one end of said electrically conductive element foralternate ejection from and retraction into a distal end of said tubularmember; a second loop having a second circumference larger than saidfirst circumference so that a simultaneous retraction of said first loopand said second loop into said distal end of said tubular member resultsin a completed retraction of said first loop while a portion of saidsecond loop still remains outside of said tubular member; an elongateconnector element, said second loop being formed at one end of saidconnector element whereby said second loop is alternately ejected fromand retracted into said tubular member; and a pouch member attached tosaid second loop along at least a portion of said second circumferenceso as to form a capture pocket with said second loop defining a mouth oropening of said capture pocket, said first loop being free all alongsaid first circumference of attachment to said pouch member.
 8. Thesnare assembly set forth in claim 7 wherein at least a portion of saidsecond loop being made of a heat resistant material and wherein saidconnector element is attached to said electrically conductive element.9. The snare assembly set forth in claim 7 wherein said first loop andsaid second loop are at least approximately coplanar in an expandedconfiguration upon ejection from said tubular member.
 10. The snareassembly set forth in claim 7 wherein said second loop is bent out of aplanar configuration.
 11. A minimally invasive surgical methodcomprising: (a) providing a medical treatment assembly including: atubular member; an elongate electrically conductive element slidablydisposed at least partially in said tubular member; a first loop havinga first circumference and made of an electrically conductive materialand provided at one end of said electrically conductive element foralternate ejection from and retraction into a distal end of said tubularmember; a second loop made at least partially of a heat resistantmaterial, said second loop having a second circumference larger thansaid first circumference so that a simultaneous retraction of said firstloop and said second loop into said distal end of said tubular memberresults in a completed retraction of said first loop while a portion ofsaid second loop still remains outside of said tubular member; anelongate connector element, said second loop being formed at one end ofsaid connector element whereby said second loop is alternately ejectedfrom and retracted into said tubular member; and a pouch member attachedto said second loop along at least a portion of said secondcircumference so as to form a capture pocket with said second loopdefining a mouth or opening of said capture pocket, said first loopbeing free all along said first circumference of attachment to saidpouch member; (b) inserting a distal end portion of said tubular memberinto a patient; (c) after the inserting of said distal end portion ofsaid tubular member into the patient, pushing said electricallyconductive element to eject said first loop from said tubular member,said first loop expanding from a collapsed configuration into an atleast partially opened configuration upon ejection of said first loopfrom said tubular member; (d) after the inserting of said distal endportion of said tubular member into the patient, pushing said connectorelement to eject said second loop from said tubular member, said secondloop expanding from a collapsed configuration into an at least partiallyopened configuration upon ejection of said second loop from said tubularmember; (e) manipulating said tubular member and said electricallyconductive element to pass the expanded first loop and the expandedsecond loop over a lump of tissue inside the patient; (f) after thepassing of the expanded first loop and the expanded second loop oversaid lump of tissue, pulling said electrically conductive element andsaid connector element to simultaneously draw said first loop and saidsecond loop into said distal end portion of said tubular member, therebycontracting said first loop and said second loop; (g) passing anelectrical current through said first loop during the pulling ofelectrically conductive element and said connector element and thecontracting of said first loop and said second loop, thereby severingsaid lump of tissue; (h) capturing the severed lump of tissue in saidcapture pocket upon a partial closure thereof owing to drawing of saidsecond loop into said distal end portion of said tubular member; and (i)maintaining a portion of said second loop outside of said tubular memberafter a completed withdrawing of said first loop into said distal endportion of said tubular member.
 12. A medical device comprising: atubular member; an electrically conductive loop ejectable from a distalend of said tubular member; and a capture pouch also ejectable from saiddistal end of said tubular member, said tubular member, saidelectrically conductive loop, and said pouch being adapted to enableretrieval of multiple tissue samples from a patient, said pouch beingattached to an auxiliary loop, said auxiliary loop having asubstantially larger circumference than a circumference of saidelectrically conductive loop so that a simultaneous retraction of saidfirst loop and said second loop into said distal end of said tubularmember results in a completed retraction of said first loop while aportion of said second loop still remains outside of said tubularmember.
 13. In a medical cauterization snare assembly comprising atubular member, an electrically conductive loop ejectable from a distalend of said tubular member, and a capture pouch also ejectable from saiddistal end of said tubular member, said loop being a first loop having afirst size, the improvement wherein said pouch is attached to a secondloop having a second size larger than said first size so that asimultaneous retraction of said first loop and said second loop intosaid distal end of said tubular member results in a completedcontraction of said first loop while a portion of said second loop stillremains outside of said tubular member, said first loop and said secondloop being at least approximately coplanar in an expanded configurationupon ejection from said tubular member.
 14. The snare assembly set forthin claim 13 wherein said first loop and said second loop are bothconnected to a common wire slidably extending through said tubularmember, at least a portion of said second loop being made of a heatresistant material.
 15. The snare assembly set forth in claim 14 whereinsaid heat resistant material is nylon.
 16. The snare assembly set forthin claim 13 wherein said second loop is bent out of a planarconfiguration.